The invention disclosed herein relates to the adjustment of advancing sheet material relative to its path of advancement. More particularly, the invention relates to adjustment of paper being advanced in a mailing machine to a station which operates on the paper, for example folds the paper and/or inserts the paper into an envelope, so that the paper is presented to the station in a desired alignment. The invention has particular application for use with apparatus which cross folds paper.
The mailing process entails a number of operations including assembly and insertion of mail items into an envelope, sealing the envelope and applying postage. Frequently, mail items are sheets of paper which may have to be folded prior to insertion into an envelope depending on the paper and envelope sizes. In some applications, it is necessary to cross fold the paper, i.e., fold the paper once, rotate the once-folded paper 90.degree., advance the once-folded paper to be folded again (cross folded), and then cross fold the paper at a 90.degree. angle to the first fold. Where the folding and/or insertion portions of the mailing process are automated, paper must be presented to the folding or inserting apparatus in proper alignment, i.e., squarely, with substantially no skew between the paper edge and the entrance to the folding or inserting apparatus. See, for example, U.S. Pat. Nos. 4,169,341 of Roetter et al., and 4,077,181 of Asher et al., both assigned to the assignee of this application.
For various reasons, sheet material may be advanced skewed relative to the path of travel thereof. This may be caused by accumulated tolerances in parts, wear, etc. In automated mailing apparatus, skewed paper presented to the folding or inserting apparatus may cause jamming which would require shut down of the mailing apparatus. High speed mailing apparatus, e.g., with several thousand mail pieces per hour throughput, is particularly prone to such jamming.
The invention disclosed herein addresses alignment of folded or unfolded sheet material as it is advanced towards the folding or insertion apparatus.